I. Field of the Invention
The present invention relates broadly to composite structural siding panels and, more particularly, to a backerboard having insulating qualities and adapted to be disposed between the inner surfaces of the siding panel and the exterior wall of a building structure.
II. Description of the Prior Art
Heretofore siding panels for buildings have been constructed of various material, such as aluminum, steel, or vinyl, manufactured in long panels of approximately 12 feet, 6 inches. The long panels are fastened horizontally in overlapping relationship to the wall of the building and, in some instances, have been applied directly over existing structures or over a sheathing of a standard type, such as Celotex or the like. It is becoming a common commercial practice to laminate the siding panel with an insulating material in the nature of a foam or rigid polystyrene or the like. Examples of such siding panels are disclosed in U.S. Pat. Nos. 2,535,620; 3,159,943; and 3,214,876. All of these structures have one thing in common; that is, the construction of the siding panel is in the form of a flat surface with outer edges contoured so as to provide for the mating attachment of the individual horizontally disposed panels. However, when siding panels of the Double-4 or Double-5 type, such as disclosed in U.S. Pat. No. 3,157,965, are desired to be used, the flat sheet of insulating material of the type disclosed in the aforementioned patents is not appropriate.
As can be seen in FIG. 1 of the drawings, an example of the prior art is illustrated in the form of a cross-sectional view of a Double-4 siding panel 10 which is formed of an aluminum material and has walls 12 and 14 separated by a step 16, while the parallel lengthwise edges 18 and 20' are contoured so as to define sections which are utilized to attach the siding panels to the building structure in a conventional manner. In order to provide an insulating backerboard, the prior art has devised a backerboard 20 of the type disclosed in FIG. 1 which consists of an integral member having first and second longitudinal walls 24 and 26 interconnected by an inclined wall 28. It can easily be seen upon inspection of FIG. 1 that an air space 29 is formed between the backerboard 20 and the siding panel 10 in the area associated with the step 16. This air space 29 may result in an unwanted accumulation of moisture and/or insects and the like.
As aforementioned, it is conventional for siding panels to be fabricated in full lengths of approximately 12 feet, 6 inches; however, the existing prior art insulating backerboard 20 may not be fabricated in lengths exceeding 75 inches. This is due to the present methods of manufacturing. Generally, a wire cutting method is employed in the manufacture of the prior art backerboard 20, and the same may not be made in an accurate and acceptable manner in lengths in excess of 75 inches.
Because of the contour of the prior art backerboard 20 and its non-uniform lengths, it is necessary that it be attached to the siding panel 10 at the building site, thus, necessitating the need for double shipments. It would be preferable and more economical to laminate the backerboard 20 to the siding panel 10 at the respective siding manufacturer's plant; however, it can be seen that the stacking of the siding panel 10 one upon the other would result in cracking or otherwise damaging the inclined section 28 of the backerboard 20. Additionally, the fact that the prior art backerboard 20 may not be fabricated in lengths in excess of 75 inches, an attempt to laminate two pieces of backerboard 20 to the siding panel 10 in an implant process has proved to be uneconomical.